A common challenge in the X-ray nanotomography of porous media, such as fuel cell gas
diffusion layers (GDLs), is to binarize nanotomography greyscale images in order to differentiate
between solids and voids for structural characterisation and numerical flow analysis. In the process
threshold determination is critical. This paper presents a study on determination of and fine-tuning
threshold value based on comparison of material porosity and average fibre diameter obtained from
nanotomography images with porosity data from density experiments and average fibre diameter
achieved from scanning electron microscopy images respectively. The more accurate 3D
reconstructed model is then used to calculate pore size distribution and average pore size, while the
gas permeability of the representative 3D binary images are calculated using a single phase Lattice
Boltzmann (LB) model in the D3Q19 regime.